Coupling Having Rotation Limited Segments

ABSTRACT

A pipe coupling has two segments with angularly oriented action surfaces in facing relationship. The action surfaces induce relative rotation between the segments when the segments are drawn together to engage the pipe elements being joined. Attachment elements on each segment, in the form of lugs, accommodate adjustable fasteners which draw the segments together when tightened. Angularly oriented support surfaces on the lugs engage one another and react the fastener force. Stop surfaces are positioned on the lugs adjacent to the support surfaces. Engagement between the stop surfaces limits the relative rotation between the segments.

This application is based upon and claims benefit of priority to U.S.Provisional Application No. 63/110,433, filed Nov. 6, 2020, whichapplication is hereby incorporated by reference herein.

Field of the Invention

This invention relates to mechanical couplings for joining pipeelements.

Background

It is advantageous to use angularly oriented interface surfaces betweenthe segments of a mechanical coupling for grooved pipe to cause thesegments to rotate relatively to one another such that the “keys” of thecoupling lock into the circumferential grooves of the pipe elements andform a more rigid joint in bending and torsion between them. U.S. Pat.No. 4,639,020 to Rung et al., hereby incorporated by reference herein,discloses an example of such a coupling.

While very effective at creating more rigid joints, such prior artcouplings may present challenges during installation, for example, inease of assembly and the lack of consistent and identical visualindication that a coupling is properly installed in all intendedconditions. There is clearly an opportunity to improve such mechanicalcouplings so they are easier to assemble and provide consistent andunambiguous visual indication confirming proper installation.

SUMMARY

The invention concerns a coupling for joining pipe elements in end toend relation. In an example embodiment the coupling comprises first andsecond segments attached to one another end to end surrounding a centralspace for receiving the pipe elements. Each segment comprises a firstlug extending from a first end thereof and a second lug extending from asecond end thereof. The first and second lugs of the first segment alignrespectively with the first and second lugs of the second segment. Afirst adjustable fastener extends between the first lugs and a secondadjustable fastener extends between the second lugs. Each segmentfurther comprises a first action surface positioned between the centralspace and the first lug, and a first support surface positioned on thefirst lug. The first fastener is positioned between the first actionsurface and the first support surface. The first action surface and thefirst support surface are oriented at a first angle transverse to alongitudinal axis of the first fastener. A second action surface ispositioned between the central space and the second lug, and a secondsupport surface positioned on the second lug. The second fastener ispositioned between the second action surface and the second supportsurface. The second action surface and the second support surface areoriented at a second angle transverse to a longitudinal axis of thesecond fastener. The second angle has an opposite slope from the firstangle. At least a first stop surface is positioned on the first lugadjacent to the first support surface. The first stop surface isoriented at a third angle having a slope opposite to the first angle. Atleast a second stop surface is positioned on the second lug adjacent tothe second support surface. The second stop surface is oriented at afourth angle having a slope opposite to the second angle. Upon adjustingthe first and second fasteners to draw the first and second segmentstoward one another, engagement between the first action surfaces at thefirst ends of the segments and engagement between the second actionsurfaces at the second ends of the segments rotates the first and secondsegments in opposite directions relative to one another, and engagementbetween at least one of the first stop surfaces on the first lugs andthe second stop surfaces on the second lugs limits the rotation.

In an example embodiment, the first lugs define a first openingsurrounding a first axis oriented perpendicularly to the longitudinalaxis of the first fastener and positioned between the first actionsurfaces and the first support surfaces. The first opening may extendthrough the first lugs. Further by way of example, the second lugsdefine a second opening surrounding a second axis orientedperpendicularly to the longitudinal axis of the second fastener andpositioned between the second action surfaces and the second supportsurfaces. The second opening may extend through the second lugs.

In an example embodiment, each one of the first and second adjustablefasteners comprises a nut and bolt. Further by way of example, each ofthe segments comprises first and second arcuate projections positionedon opposite sides of the segments. Each of the arcuate projections facethe central space. Each of the arcuate projections is engageable withincircumferential grooves in the pipe elements when the segments are drawntoward one another by the adjustable fasteners. An example embodimentmay further comprise a seal positioned within the central space. Theseal supports the segments in spaced apart relation sufficient to permitinsertion of the pipe elements into the central space withoutdisassembling the coupling. In a practical example the first angle has aslope of 45° and may also have a slope ranging from 30° to 60°. By wayof example, the second angle has an equal but opposite slope to thefirst angle.

The invention further encompasses a coupling for joining pipe elementsin end to end relation. An example coupling embodiment comprises firstand second segments attached to one another end to end surrounding acentral space for receiving the pipe elements. Each segment comprises afirst lug extending from a first end thereof and a second lug extendingfrom a second end thereof. The first and second lugs of the firstsegment align respectively with the first and second lugs of the secondsegment. A first adjustable fastener extends between the first lugs anda second adjustable fastener extends between the second lugs. Eachsegment further comprises a first action surface positioned between thecentral space and the first lug, and a first support surface positionedon the first lug. The first fastener is positioned between the firstaction surface and the first support surface. The first action surfaceis oriented perpendicularly to a longitudinal axis of the firstfastener, and the first support surface is oriented at a first angletransverse to the longitudinal axis of the first fastener. A secondaction surface is positioned between the central space and the secondlug, and a second support surface is positioned on the second lug. Thesecond fastener is positioned between the second action surface and thesecond support surface. The second action surface is orientedperpendicularly to a longitudinal axis of the second fastener, and thesecond support surface is oriented at a second angle transverse to thelongitudinal axis of the second fastener. The second angle has anopposite slope from the first angle. At least a first stop surface ispositioned on the first lug adjacent to the first support surface. Thefirst stop surface is oriented at a third angle having a slope oppositeto the first angle. At least a second stop surface is positioned on thesecond lug adjacent to the second support surface. The second stopsurface is oriented at a fourth angle having a slope opposite to thesecond angle. Upon adjusting the first and second fasteners to draw thefirst and second segments toward one another, engagement between atleast one of the first stop surfaces on the first lugs and the secondstop surfaces on the second lugs arrests rotation of the segmentsrelatively to one another.

In an example embodiment the first lugs define a first openingsurrounding a first axis oriented perpendicularly to the longitudinalaxis of the first fastener and positioned between the first actionsurfaces and the first support surfaces. The first opening may extendthrough the first lugs. Further by way of example the second lugs definea second opening surrounding a second axis oriented perpendicularly tothe longitudinal axis of the second fastener and positioned between thesecond action surfaces and the second support surfaces. The secondopening may extend through the second lugs. In a specific exampleembodiment, each one of the first and second adjustable fastenerscomprises a nut and bolt.

In an example embodiment, each of the segments comprises first andsecond arcuate projections positioned on opposite sides of the segments.Each of the arcuate projections faces the central space. Each of thearcuate projections is engageable within circumferential grooves in thepipe elements when the segments are drawn toward one another by theadjustable fasteners.

An example embodiment may further comprise a seal positioned within thecentral space. The seal supports the segments in spaced apart relationsufficient to permit insertion of the pipe elements into the centralspace without disassembling the coupling. In a practical example, thefirst angle has a slope of 45° and may have a slope ranging from 30° to60°. In a specific example embodiment the second angle has an equal butopposite slope to the first angle.

The invention also encompasses a coupling for joining pipe elements inend to end relation. In an example embodiment the coupling comprisesfirst and second segments attached to one another end to end surroundinga central space for receiving the pipe elements. Each segment comprisesa first lug extending from a first end thereof. The first lug of thefirst segment aligns with the first lug of the second segment. A firstadjustable fastener extends between the first lugs. Each segment furthercomprises a second end. The second ends of the segments are arrangedopposite to the first ends respectively. Each second end is connected toa hinge joining the first and second segments to one another. The hingedefines a hinge axis oriented perpendicularly to a longitudinal axis ofthe first fastener. The first and second segments are pivotable aboutthe hinge axis. By way of example each segment further comprises a firstaction surface positioned between the central space and the first lug,and a first support surface positioned on the first lug. The firstfastener is positioned between the first action surface and the firstsupport surface. The first action surface is oriented perpendicularly tothe longitudinal axis of the first fastener, and the first supportsurface is oriented at a first angle transverse to the longitudinal axisof the first fastener. A first stop surface is positioned on the firstlug adjacent to the first support surface. The first stop surface isoriented at a third angle having a slope opposite to the first angle.Upon adjusting the first fastener to pivot and thereby draw the firstand second segments toward one another, engagement between the firststop surfaces on the first lugs arrests rotation of the segmentsrelatively to one another.

In an example embodiment the first lugs define a first openingsurrounding a first axis oriented perpendicularly to the longitudinalaxis of the first fastener and positioned between the first actionsurfaces and the first support surfaces. The first opening may extendthrough the first lugs. In a practical example the first adjustablefastener comprises a nut and bolt.

By way of example, each of the segments comprises first and secondarcuate projections positioned on opposite sides of the segments. Eachof the arcuate projections faces the central space. Each of the arcuateprojections is engageable within circumferential grooves in the pipeelements when the segments are drawn toward one another by theadjustable fastener. A coupling according to the invention may furthercomprise a seal positioned within the central space. The seal supportsthe segments in spaced apart relation sufficient to permit insertion ofthe pipe elements into the central space without disassembling thecoupling.

In a practical example, the first angle has a slope of 45° and may havea slope ranging from 30° to 60°.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an example mechanical coupling accordingto the invention shown in a factory assembled state;

FIG. 2 is an end view of the coupling shown in FIG. 1;

FIGS. 3 and 4 show end views of the example coupling duringinstallation;

FIG. 5 is an isometric view of another example mechanical couplingaccording to the invention shown in a factory assembled state;

FIG. 6 is an end view of the coupling shown in FIG. 5;

FIGS. 7 and 8 show end views of the example coupling duringinstallation; and

FIG. 9 is a front view of another example embodiment of a couplingaccording to the invention.

DETAILED DESCRIPTION

FIG. 1 shows an example coupling 10 according to the invention forjoining pipe elements (not shown) in end to end relation. In thisexample the coupling 10 comprises a first segment 12 and a secondsegment 14. Segments 12 and 14 are attached to one another end to end tosurround and define a central space 16 for receiving the pipe elements.Coupling 10 is designed to join pipe elements having circumferentialgrooves at an end and thus each of the segments 12 and 14 comprisesfirst and second arcuate projections 18 a and 18 b (see also FIG. 2),also known as “keys”, positioned on opposite sides 20 and 22 of thesegments 12 and 14. The arcuate projections 18 a and 18 b face thecentral space 16 and are engageable within circumferential grooves inthe pipe elements when the segments are drawn toward one another to forma joint. A seal 24 is positioned within the central space 16. Seal 24 isadvantageously a ring gasket made of an elastomer such as EPDM, and maysupport the segments 12 and 14 in spaced apart relation as shown, at adistance sufficient to permit insertion of the pipe elements into thecentral space 16 without disassembling the coupling 10. Couplingsaccording to the invention may also be used with plain end pipe,shouldered pipe or other formed pipe ends known in the art.

As further shown in FIG. 1, each segment 12, 14 comprises a first lug 26extending from first ends 28 thereof. A second lug 30 extends from asecond end 32 of each segment. The first and second lugs 26 and 30 ofthe first segment 12 align respectively with the first and second lugs26 and 30 of the second segment 14. A first adjustable fastener 34extends between the first lugs 26 of each segment 12 and 14, and asecond adjustable fastener 36 extends between the second lugs 30 of eachsegment. In this example the first and second adjustable fasteners 34and 36 comprise a nut 38 and bolt 40.

Each segment 12 and 14 further comprises a first action surface 42positioned between the central space 16 and the first lug 26. A firstsupport surface 44 is positioned on the first lug 26 of each segment 12and 14. The first fastener 34 is positioned between the first actionsurfaces 42 and the first support surfaces 44 of the segments 12 and 14.As shown in FIGS. 1 and 2, the first action surfaces 42 and the firstsupport surfaces 44 are oriented at a first angle 46 transverse to alongitudinal axis 48 of the first fastener 34. The first angle 46 mayhave a slope ranging from 45° to 70°, with a slope of 60° consideredadvantageous. As shown in FIG. 1, a second action surface 50 ispositioned between the central space 16 and the second lug 30 on eachsegment 12 and 14. A second support surface 52 is positioned on thesecond lugs 30 of each of the segments 12 and 14. The second fastener 36is positioned between the second action surfaces 50 and the secondsupport surfaces 52 of the segments 12 and 14. The second actionsurfaces 50 and the second support surfaces 52 are oriented at a secondangle 54 transverse to a longitudinal axis 56 of the second fastener 36.The second angles 54 of the second action surfaces 50 and the secondsupport surfaces 52 have an opposite slope from the first angle 46 ofthe first action surfaces 42 and the first support surfaces 44. It isadvantageous if the slopes of the first and second angles 46 and 54 arealso equal in magnitude as well as opposite in sign. Although, in theembodiments disclosed in this specification, the first and second actionsurfaces 42 and 50 have the same angular orientations as the first andsecond support surfaces 44 and 52 respectively, a practical design mayalso advantageously have action surfaces with orientation angles whichdiffer from the orientation angles of their adjacent associated supportsurfaces.

At least a first stop surface 58 is positioned on the first lugs 26 ofeach segment 12 and 14 adjacent to the first support surfaces 44. Thefirst stop surfaces 58 are oriented at a third angle 60 (see FIG. 1)having a slope opposite to the slope of the first angle 46. At least asecond stop surface 62 is positioned on the second lugs 30 of eachsegment 12, 14 adjacent to the second support surfaces 52. The secondstop surfaces 62 are oriented at a fourth angle 64 having a slopeopposite to the second angle 54.

Advantageously, the first lugs 26 may define a first opening 27surrounding a first axis 29 oriented perpendicularly to the longitudinalaxis 48 of the first fastener 34 and positioned between the first actionsurfaces 42 and the first support surfaces 44. In a practicalembodiment, the first opening 27 extends through the first lugs 26. Thebending stiffness of the first lugs 26 may be tuned to a desired valueby properly sizing the first opening 27. Similarly, the second lugs 30may define a second opening 31 surrounding a second axis 33 orientedperpendicularly to the longitudinal axis 56 of the second fastener 36and positioned between the second action surfaces 50 and the secondsupport surfaces 52. In a practical embodiment, the second opening 31extends through the second lugs 30. The bending stiffness of the secondlugs 30 may be tuned to a desired value by properly sizing the secondopening 31.

Operation of coupling 10 is described with reference to FIGS. 1-4. FIGS.1 and 2 show the example coupling 10 in the factory assembledconfiguration with segments 12 and 14 supported in spaced apart relationon seal 24 at a distance from one another sufficient to permit pipeelements (not shown) to be inserted into the central space 16. In thisfactory assembled example fasteners 34 and 36 have been tightenedsufficiently to hold the segments against the seal. The pipe elementsare inserted into central space 16 and their circumferential grooves arealigned with the arcuate projections 18 a and 18 b on opposite sides 20and 22 of the segments 12 and 14. Fasteners 34 and 36 are then furthertightened to draw segments 12 and 14 toward one another. FIG. 3 showsthe point when the first and second action surfaces 42 and 50 onsegments 12 and 14 engage one another (42 shown). Advantageously,support surfaces 44 and 52 on each segment engage at approximately thesame time (44 shown). Arcuate projections 18 a and 18 b (not visible inthe figure) are also engaged within the grooves of the pipe elements atthis point as well. During correct installation of coupling 10,engagement of the support surfaces 44 and 52 between the segments 12 and14 provide a first visual indication confirming that correctinstallation is proceeding.

The angular orientation and opposite slopes of the action surfaces 42and 50 and the support surfaces 44 on the first end 28 of the segmentsand support surfaces 52 on the second end 30 cause the segments 12 and14 to rotate in opposite directions relatively to one another asfasteners 34 and 36 are further tightened. FIG. 1 illustrates the axisof rotation 66 of the segments as the pair of action surfaces 42 and thepair of action surfaces 50 on each segment engage one another. Theobject of this rotation is to force the arcuate projections 18 a and 18b to securely contact the sidewalls and/or the floors of thecircumferential grooves of the pipe elements which they engage andthereby increase the rigidity of the joint in bending, axial loading,and torsion. Note, however, that the action surfaces 42 and 50 have nofeature which limits the degree of relative rotation between thesegments 12 and 14 as the fasteners are tightened. A feature whichlimits the relative rotation between the segments 12 and 14 is providedby the respective stop surfaces 58 and 62 on the lugs 26 and 30. Asshown in FIG. 4, these stop surfaces (58 shown) engage as the fastenersare further tightened. The geometry of the action surfaces 42 and 50,the support surfaces 44 and 52, and the stop surfaces 58 and 62, theirlengths, positions on the segments and orientation angles arecoordinated with the arcuate projections 18 a and 18 b such that theprojections lock up effectively within the circumferential grooves ofthe pipe elements when the first stop surfaces 58 and the second stopsurfaces 62 respectively engage, or nearly engage as depicted in FIG. 4.Thus engagement of both stop surfaces 58 and 62 on opposite ends of thesegments 12 and 14 provides visual confirmation that the coupling 10 hasbeen properly installed. The stop surface 58 and 62 provide thisconfirmation over the entire tolerance range imposed on thecircumferential grooves in the pipe elements. At one end of the groovetolerance range the segments 12 and 14 rotate about axis 66 to the limitimposed by respective engagement between the first stop surfaces 58 andthe second stop surfaces 62. At the other end of the groove tolerancerange engagement between one or both projections 18 a and 18 b and theirrespective circumferential grooves impose the limit on segment rotation.It is conceivable that when engagement between the projections 18 a and18 b and the grooves limits segment relative rotation that one or bothof the first and second stop surfaces 58 and 62 will not be engaged.However, the lugs 26 and 30 at opposite ends of the segments 12 and 14are designed to deform when fasteners 34 and 36 are tightened once therotational limit imposed by engagement between the projections 18 a and18 b and their circumferential grooves is reached to permit the stopsurfaces 58 and 62 to engage. The deformation is controlled in part bythe size of the openings 27 and 29 which extend through the lugs 26 and30. Thus, regardless of where the circumferential grooves in the pipeelements fall on the tolerance spectrum the technician needs merely totighten the fasteners 34 and 36 until the stop surfaces 58 and 62 onrespective lugs 26 and 30 at respective opposite ends 28 and 32 ofsegments 12 and 14 engage. This engagement provides a final visualconfirmation that the coupling 10 has been properly installed.

In addition to being readily visually inspected to confirm a properjoint, couplings 10 according to the invention are also relativelyinsensitive to the installation procedure, affording greater ease ofassembly. While a preferred installation practice is to partiallytighten each fastener in a series of alternating steps, this practicemay not always be followed. Instead, a technician may apply a poweredimpact wrench and fully tighten one fastener and then the other.However, with couplings 10 according to the invention this practice doesnot result in over-rotation of the coupling segments, which is preventedby engagement of the stop surfaces on the side of the one fastener whichis first tightened. The technician may then apply torque to tighten theother fastener to bring the stop surfaces on the opposite end of thecoupling into engagement to complete the installation. The geometry ofthe couplings is such that as long as both sets of stop surfaces 58 and62 are in contact, the projections 18 a and 18 b will be securelyengaged within their respective circumferential grooves, in contact withthe groove sidewalls and/or floors to form a rigid joint.

FIGS. 5-8 illustrate another example embodiment of a coupling 70according to the invention. Coupling 70 is identical to coupling 10 asdescribed above except for the orientation of the action surfaces 42 and50. In coupling 70, the first action surface 42 is orientedsubstantially perpendicularly to the longitudinal axis 48 of the firstfastener 34 and the second action surface 50 is oriented substantiallyperpendicularly to the longitudinal axis 56 of said second fastener 36.Due to the different orientation of the action surfaces 42 and 50 thecoupling segments 12 and 14 do not rotate about axis 66 upon theirengagement when the fasteners 34 and 36 are tightened to bring thesegments toward one another to couple pipe elements to one another.Coupling 70 is advantageous when a more flexible pipe joint is desired.However, when the fasteners 34 and 36 are tightened, friction betweenthe torqued fastener and its respective lug tends to rotate the couplingsegments relatively to one another, thereby causing unwanted engagementbetween the projections 18 a and 18 b and the grooves in the pipeelements. As shown in FIGS. 7 and 8, this unwanted effect is mitigatedby engagement between one or both of the stop surfaces 58 and 62 on thelugs 26 and 30 because the geometry of the support surfaces 44 and 52,and the stop surfaces 58 and 62, their lengths, positions on thesegments and orientation angles are coordinated with the arcuateprojections 18 a and 18 b such that the projections will not lock upwithin the circumferential grooves of the pipe elements when the firststop surfaces 58 and the second stop surfaces 62 respectively engage.Engagement between the stop surfaces and support surfaces may also serveas final visual confirmation that the coupling 70 has been properlyinstalled.

FIG. 9 illustrates another example embodiment of a coupling 72 accordingto the invention. Coupling 72 shares many of the features of couplingembodiments 10 and 70 as described above but substitutes a hinge inplace of the second lugs 30. The second ends 32 of each segment 12 and14, arranged opposite to the first ends 28, are connected to a hinge 74joining the first and second segments to one another. The hinge 74defines a hinge axis 76 oriented perpendicularly to the longitudinalaxis 48 of the first fastener 34. The first and second segments 12 and14 are pivotable about the hinge axis 76. Adjusting the first fastener34 pivots and thereby draws the first and second segments 12 and 14toward one another, and engagement between the first stop surfaces 58 onthe first lugs 26 (see FIG. 8) arrests rotation of the segmentsrelatively to one another about the axis 66. In this example embodiment,hinge 74 comprises bearings 78 (shown) and 80 (hidden) rotatably joinedby a hinge pin 82. Other forms of hinged joints are also practical.

As for coupling 70, the first action surfaces 42 of coupling 74 areoriented substantially perpendicularly to the longitudinal axis 48 ofthe first fastener 34. Due to the perpendicular orientation of theaction surfaces 42, the coupling segments 12 and 14 do not rotaterelatively to one another about axis 66 upon their engagement when thefastener 34 is tightened to bring the segments toward one another tocouple pipe elements to one another. Like coupling 70, coupling 74 isadvantageous when a more flexible pipe joint is desired. When thefastener 34 is tightened, friction between the torqued fastener and itsrespective lug tends to rotate the coupling segments relatively to oneanother, thereby causing unwanted engagement between the projections 18a and 18 b and the grooves in the pipe elements. Similar to coupling 70and shown in FIGS. 7 and 8 (which also illustrate lugs 26 of coupling74), this unwanted effect is mitigated by engagement between one or bothof the stop surfaces 58 on the lugs 26 because the geometry of thesupport surfaces 44 and the stop surfaces 58, their lengths, positionson the segments and orientation angles are coordinated with the arcuateprojections 18 a and 18 b such that the projections will not lock upwithin the circumferential grooves of the pipe elements when the firststop surfaces 58 engage. Engagement of the stop surfaces also preventsunwanted torsion loads on the hinge about an axis perpendicular torotation axis 76. Engagement between the stop surfaces and supportsurfaces may also serve as final visual confirmation that the coupling74 has been properly installed. The stop surfaces provide thisconfirmation over the entire tolerance range imposed on the diameter ofthe circumferential grooves in the pipe elements.

As with couplings 10 and 70, the first lugs 26 of coupling 74 define afirst opening 27 surrounding a first axis 29 oriented perpendicularly tothe longitudinal axis 48 of the first fastener 34. Axis 48 and fastener34 are positioned between the first action surfaces 42 and the firstsupport surfaces 44. In the example embodiment shown the first opening27 extends through said first lugs 26. In a practical embodiment, thefirst adjustable fastener 34 may comprise a nut 38 and bolt 40.

It is expected that couplings according to the invention will permitboth rigid and flexible joints to be formed easily and reliably whilereducing the coupling's sensitivity to poor installation techniques.

What is claimed is:
 1. A coupling for joining pipe elements in end toend relation, said coupling comprising: first and second segmentsattached to one another end to end surrounding a central space forreceiving said pipe elements, each said segment comprising a first lugextending from a first end thereof and a second lug extending from asecond end thereof, said first and second lugs of said first segmentaligning respectively with said first and second lugs of said secondsegment; a first adjustable fastener extending between said first lugsand a second adjustable fastener extending between said second lugs;wherein each said segment further comprises: a first action surfacepositioned between said central space and said first lug, and a firstsupport surface positioned on said first lug, said first fastener beingpositioned between said first action surface and said first supportsurface, said first action surface and said first support surface beingoriented at a first angle transverse to a longitudinal axis of saidfirst fastener; a second action surface positioned between said centralspace and said second lug, and a second support surface positioned onsaid second lug, said second fastener being positioned between saidsecond action surface and said second support surface, said secondaction surface and said second support surface being oriented at asecond angle transverse to a longitudinal axis of said second fastener,said second angle having an opposite slope from said first angle; atleast a first stop surface positioned on said first lug adjacent to saidfirst support surface, said first stop surface being oriented at a thirdangle having a slope opposite to said first angle; at least a secondstop surface positioned on said second lug adjacent to said secondsupport surface, said second stop surface being oriented at a fourthangle having a slope opposite to said second angle; wherein uponadjusting said first and second fasteners to draw said first and secondsegments toward one another, engagement between said first actionsurfaces at said first ends of said segments and engagement between saidsecond action surfaces at said second ends of said segments rotates saidfirst and second segments in opposite directions relative to oneanother, and engagement between at least one of said first stop surfaceson said first lugs and said second stop surfaces on said second lugslimits said rotation.
 2. The coupling according to claim 1, wherein saidfirst lugs define a first opening surrounding a first axis orientedperpendicularly to said longitudinal axis of said first fastener andpositioned between said first action surfaces and said first supportsurfaces.
 3. The coupling according to claim 2, wherein said firstopening extends through said first lugs.
 4. The coupling according toclaim 2, wherein said second lugs define a second opening surrounding asecond axis oriented perpendicularly to said longitudinal axis of saidsecond fastener and positioned between said second action surfaces andsaid second support surfaces.
 5. The coupling according to claim 4,wherein said second opening extends through said second lugs.
 6. Thecoupling according to claim 1, wherein each one of said first and secondadjustable fasteners comprises a nut and bolt.
 7. The coupling accordingto claim 1, wherein each of said segments comprises first and secondarcuate projections positioned on opposite sides of said segments, eachof said arcuate projections facing said central space, each of saidarcuate projections being engageable within circumferential grooves insaid pipe elements when said segments are drawn toward one another bysaid adjustable fasteners.
 8. The coupling according to claim 1, furthercomprising a seal positioned within said central space, said sealsupporting said segments in spaced apart relation sufficient to permitinsertion of said pipe elements into said central space withoutdisassembling said coupling.
 9. The coupling according to claim 1,wherein said first angle has a slope of 45°.
 10. The coupling accordingto claim 1, wherein said first angle has a slope ranging from 30° to60°.
 11. The coupling according to claim 1, wherein said second anglehas an equal but opposite slope to said first angle.
 12. A coupling forjoining pipe elements in end to end relation, said coupling comprising:first and second segments attached to one another end to end surroundinga central space for receiving said pipe elements, each said segmentcomprising a first lug extending from a first end thereof and a secondlug extending from a second end thereof, said first and second lugs ofsaid first segment aligning respectively with said first and second lugsof said second segment; a first adjustable fastener extending betweensaid first lugs and a second adjustable fastener extending between saidsecond lugs; wherein each said segment further comprises: a first actionsurface positioned between said central space and said first lug, and afirst support surface positioned on said first lug, said first fastenerbeing positioned between said first action surface and said firstsupport surface, said first action surface being orientedperpendicularly to a longitudinal axis of said first fastener, and saidfirst support surface being oriented at a first angle transverse to saidlongitudinal axis of said first fastener; a second action surfacepositioned between said central space and said second lug, and a secondsupport surface positioned on said second lug, said second fastenerbeing positioned between said second action surface and said secondsupport surface, said second action surface being orientedperpendicularly to a longitudinal axis of said second fastener, and saidsecond support surface being oriented at a second angle transverse tosaid longitudinal axis of said second fastener, said second angle havingan opposite slope from said first angle; at least a first stop surfacepositioned on said first lug adjacent to said first support surface,said first stop surface being oriented at a third angle having a slopeopposite to said first angle; at least a second stop surface positionedon said second lug adjacent to said second support surface, said secondstop surface being oriented at a fourth angle having a slope opposite tosaid second angle; wherein upon adjusting said first and secondfasteners to draw said first and second segments toward one another,engagement between at least one of said first stop surfaces on saidfirst lugs and said second stop surfaces on said second lugs arrestingrotation of said segments relatively to one another.
 13. The couplingaccording to claim 12, wherein said first lugs define a first openingsurrounding a first axis oriented perpendicularly to said longitudinalaxis of said first fastener and positioned between said first actionsurfaces and said first support surfaces.
 14. The coupling according toclaim 13, wherein said first opening extends through said first lugs.15. The coupling according to claim 13, wherein said second lugs definea second opening surrounding a second axis oriented perpendicularly tosaid longitudinal axis of said second fastener and positioned betweensaid second action surfaces and said second support surfaces.
 16. Thecoupling according to claim 15, wherein said second opening extendsthrough said second lugs.
 17. The coupling according to claim 12,wherein each one of said first and second adjustable fasteners comprisesa nut and bolt.
 18. The coupling according to claim 12, wherein each ofsaid segments comprises first and second arcuate projections positionedon opposite sides of said segments, each of said arcuate projectionsfacing said central space, each of said arcuate projections beingengageable within circumferential grooves in said pipe elements whensaid segments are drawn toward one another by said adjustable fasteners.19. The coupling according to claim 12, further comprising a sealpositioned within said central space, said seal supporting said segmentsin spaced apart relation sufficient to permit insertion of said pipeelements into said central space without disassembling said coupling.20. The coupling according to claim 12, wherein said first angle has aslope of 45°.
 21. The coupling according to claim 12, wherein said firstangle has a slope ranging from 30° to 60°.
 22. The coupling according toclaim 12, wherein said second angle has an equal but opposite slope tosaid first angle.
 23. A coupling for joining pipe elements in end to endrelation, said coupling comprising: first and second segments attachedto one another end to end surrounding a central space for receiving saidpipe elements, each said segment comprising a first lug extending from afirst end thereof, said first lug of said first segment aligning withsaid first lug of said second segment; a first adjustable fastenerextending between said first lugs; each said segment further comprisinga second end, said second ends of said segments arranged opposite tosaid first ends respectively, each said second end connected to a hingejoining said first and second segments to one another, said hingedefining a hinge axis oriented perpendicularly to a longitudinal axis ofsaid first fastener, said first and second segments being pivotableabout said hinge axis; wherein each said segment further comprises: afirst action surface positioned between said central space and saidfirst lug, and a first support surface positioned on said first lug,said first fastener being positioned between said first action surfaceand said first support surface, said first action surface being orientedperpendicularly to said longitudinal axis of said first fastener, andsaid first support surface being oriented at a first angle transverse tosaid longitudinal axis of said first fastener; a first stop surfacepositioned on said first lug adjacent to said first support surface,said first stop surface being oriented at a third angle having a slopeopposite to said first angle; wherein upon adjusting said first fastenerto pivot and thereby draw said first and second segments toward oneanother, engagement between said first stop surfaces on said first lugsarresting rotation of said segments relatively to one another.
 24. Thecoupling according to claim 23, wherein said first lugs define a firstopening surrounding a first axis oriented perpendicularly to saidlongitudinal axis of said first fastener and positioned between saidfirst action surfaces and said first support surfaces.
 25. The couplingaccording to claim 24, wherein said first opening extends through saidfirst lugs.
 26. The coupling according to claim 23, wherein said firstadjustable fastener comprises a nut and bolt.
 27. The coupling accordingto claim 23, wherein each of said segments comprises first and secondarcuate projections positioned on opposite sides of said segments, eachof said arcuate projections facing said central space, each of saidarcuate projections being engageable within circumferential grooves insaid pipe elements when said segments are drawn toward one another bysaid adjustable fastener.
 28. The coupling according to claim 23,further comprising a seal positioned within said central space, saidseal supporting said segments in spaced apart relation sufficient topermit insertion of said pipe elements into said central space withoutdisassembling said coupling.
 29. The coupling according to claim 23,wherein said first angle has a slope of 45°.
 30. The coupling accordingto claim 23, wherein said first angle has a slope ranging from 30° to60°.